Corona proof link



Jan. '6, 1959 K. G. SMITH ET AL CORONA PROOF LINK Filed Feb. 25, 1955 INVENTORS SMITH GEORGE H. WASHINGTON KENNETH G.

Z3- 1' D -4 M ATTORNEYS United Eittes Patent 2,867,682 CORONA PROOF LINK Kenneth G. Smith, Linthicum l-leightgand George H. Washington, Ellicott City, Md., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application February 25, 1955, Serial No. 490,703 3 Claims. (Cl. 174140) The present invention relates to a corona proof link and more particularly to a novel construction wherein an insulator suspended from a main supporting structure is joined to a conductor to be supported in such a way that the formation of corona is prevented.

It is the usual practice for conductors carrying very high voltage circuits to be supported in space in order to obtain proper insulation. The support utilizes any of the well-known suspension type insulators and at each insulator corona shields are necessary to equalize the stress between the air and the insulator dielectric.

It is known that when the continuous potential between a wire and a source of opposite polarity is increased a voltage will be reached at which a pale violet light called corona can be seen in the dark surrounding the wire. The glow starts first at the point of maximum gradient or at the conductor surface. The air is actually broken down and is conducting and thereby increases the effective diameter of the conductor thereby increasing the possibility of flash over. The formation of corona also results in line losses.

In the mechanics of using the suspension type of insulator it is frequently difficult .to make a direct connection between the end of the insulator and the conductor because of physical interference between a corona shield provided to eliminate the phenomena of corona and the conductor itself, or other elements. This is especially true when connections are to be made between insulators and conductors which do not intersect at a 90 angle. In order to obviate this physical interference an intermediate link between the suspension point and the conductor is necessary. However, moving the suspension point away from the conductor will reduce the effect of the corona shield at the connection itself and make it a possible source of corona and subsequent voltage breakdown. This invention enables connection between an insulator and conductor which obviates the above disadvantages by providing a corona proof link which may be made virtually any length for joining the insulator to the conductor which comprises a spherical body of a size dependent on the spacing between insulator and conductor with an axial strength member therethrough. The spherical body is arranged tangent to the conductor at one end and is within the protective -influence of a corona shield at the other end, as will later be more particularly pointed out.

It is therefore a primary object of this invention to provide a novel corona proof link adapted to be attached to existing insulators for the purpose of connecting the same to a conductor.

Another object of the invention is to provide a connector to join an insulator with a conductor that presents a symmetrical electro-statically strain free surface from the insulator to the conductor.

It is a further object of my invention to provide an insulating link which will distribute the electric flux so that the potential gradient is substantially uniform at all points along the insulating member.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Patented Jan. 6, 1959 The single figure is a perspective view showing a supporting structure with an insulator depending therefrom, and a link interconnecting the insulator with a conductor.

Referring now to the drawing there is shown a main supporting structure 5 which may be of any well-known configuration. An insulator 12 depends from the supporting structure and terminates in a bell cap 26 substantially as shown. Spokes 16 radiate outwardly from the bell cap and connect between the cap and a corona ring 14. The bottom of the bell cap is bifurcated to receive therein theend of a shaft 20 thereby forming with pin member 2 a pivoting joint. Shaft 20 is connected by bolting or other equivalent to conductor 10 substantially as shown. A spherical body, reference character 18, is axially received upon the shaft and is disposed tangent to the conductor at one end as shown, and is close within the protective influence of the main corona ring 14 at the other end. Thus the ball presents a smooth symmetrical electro-statically strain free surface continuously from the conductor to the termination of the insulator thereby allowing mechanical freedom without the provision of surfaces susceptible to the formation of corona.

Applicants have provided a link for joining a conductor to an insulated suspension member which will at once provide a high degree of mechanical freedom and eliminate the possibility of the formation of corona. It will be readily seen that a suspension made in accordance with the foregoing disclosure may readily connect insulators to conductors regardless of the angle between their several longitudinal axes.

It should be understood of course that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as set forth in the appended claims.

What is claimed is:

1. A high potential insulating device for suspending an electrical conductor from a main supporting structure comprising, a rod-type insulator adapted to depend from said supporting structure, a torus-shaped corona ring attached to the distal end of said insulator, a rod-type link having an end pivotally attached to the distal end of said insulator, a pivotal mounting on the other end of said link for attachment to said conductor at angles other than to the axis of said conductor, and a smooth surfaced, corona prevention body having a maximum diameter smaller than the outer diameter of said corona ring mounted on said link adjacent said pivotal mounting I References Cited in the file of this patent UNITED STATES PATENTS 1,426,981 Goddard Aug. 22, 1922 1,730,169 Smith Oct. 1, 1929 1,997,627 Casey Apr. 16, 1935 2,415,404 Baller Feb. 11, 1947 2,440,828 Nichols May 4, 1948 FOREIGN PATENTS 29,003 Great Britain Apr. 23, 1914 

